Dramatic gains have been made in childhood cancer including markedly more effective therapy, insights into the biology of these diseases, a clearer definition of etiologic factors, and a new focus on the outcomes of the survivors of these diseases. These gains have largely been facilitated by the cooperative clinical trials groups. This grant will facilitate the continued involvement of the investigators at the University of Minnesota in the multi-institutional cooperative therapeutic and non- therapeutic studies conducted by the Children's Cancer Group (CCG). Minnesota investigators have been at the forefront of all of these venues over the past grant cycle and are poised to continue this productive relationship into the future. In 1997, the Minnesota consortium registered 162 patients on therapeutic trials (phase I, II, and III) and, in addition, registered patients on almost 100 non-therapeutic (biology, epidemiology) studies. The combination of strong patient accrual, data management, group leadership, and authorship of CCG publications resulted in Minnesota being ranked first among all group institutions in 1995, 1996, and 1997. Minnesota investigators have continued strong leadership roles in Epidemiology and Cancer Control, Hematopoetic Stem Cell Transplantation, acute lymphoblastic and acute myeloid leukemia, biology, and experimental therapeutics. Over the past grant cycle, Minnesota investigators have chaired fourteen group therapeutic or scientific committees and served as vice-chairs on an additional twenty four. Minnesota has consistently led the group in first- authorship of group publications. Institutional research in stem cell transplantation, epidemiology and cancer control, experimental therapeutics, and biology has been applied to group studies and future investigations of all of these areas are under development. This grant requests support for the personnel critical to our future group activities. It will assure continued excellence in data management, allow travel by investigators and other key personnel to group meetings, and supply the funds needed for expenses generated by the accrual of patients to group studies. This funding will assure the continued leadership of Minnesota investigators in all aspects of the Children's Cancer Group over the coming five years.